This project attempts to describe the total range of antigens expressed on murine plasmacytomas, to evlauate their ability to induce tumor specific responses under various conditions of immunization and to assess which of these antigens are primarily involved in tumor specific immunity in the natural in vivo situation of exposure to a growing tumor. This work involves both in vitro and in vivo analysis of a range of tumor antigens. Particularly concentrating on the specificity of in vitro generated immune responses in relation to the nature of antigens on the surface of these tumors as studied by virus isolation and by cell surface iodination methods. Present studies are directed towards four different types of antigens present on plasmacytomas: (1) common plasma cell tumor antigens present on a variety of different plasmacytomas, but not present on any other tumors, (2) antigens unique to NZB derived plasma cell tumors, (3) antigen shared between plasma cell tumors and lymphomas but not present on any other tumor types, and (4) antigens present on plasma cell tumors and on a wide variety of other tumors, and present in fetal but not adult normal tissues. This project also involves ascertainment of the specificity of natural cytotoxic cells capable of lysing plamacytoma and other lymphoma tumor targets. BIBLIOGRAPHIC REFERENCE: Chism, S., Burton R. and Warner, N.L. Lymphocyte activation in vitro to murine oncofetal antigens. Nature 257, 594, 1975.